Radiocircuits



. Jan. 8, 1929, 1,697,943

W. WURST RADIO CIRCUITS Filed Jan. 11, 1927 kifi/Vil? fly. Z

' .St'A/Dik L8 g L -K!CIVR INVENTOR ALTER WURST TTORNEY Patented Jan. 8, T3255.

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WALTER wunsr, on rennnrn, enniuan'ayassrenon T0 GESELLSCHAFT, nun nearer on BERLIN, GERMANY, A conronar onor can nanroc ncurrs.

Application filed January 11, 1927, Serial No. 156,343, and in Germany January 18, 1926! This invention. relates to interference elimination, and is equally applicable to elimination of undesired signal disturbances or atmospheric disturbances, or to duplex operation, that is, transmission and reception upon asingle antenna.

The specification is accompanied by a drawing in which Figure 1 is a wiring diagram for a simple receiver equipped with devices ac-,

cording to my invention; and Figure 2 is a Wiring diagram of a duplex arrangement.

This invention relates to a coupling device adapted to eliminate any disturbances differing from the frequency of the oscillations to be received. Special ,lields of application of this invention are arrangements for duplex work both for wire-guided radio frequency intelligence transmission as well as for space telephony in which the receiving circuit is coupled with one and the same circuit upon which the local generator comes to act. In arrangements of this kind it is, as is Well known, necessary to preclude the oscillations of the localtransmit-t-er from the receiving system. For this purpose, several waysand means have been suggested based upon the use of stopper circuits and short-circuiting branches. From these well known arrangements, the subject matter of the invention differs and distinguishes itself by particularly great simplicity. and suitab-leness. According to the invention, in thecircuit intended to carry the oscillations to be received, for instance, theantenna, there is inserted a sort of differential transformer made up of two parallel connected coils which are'brought to act upon a third 0011, the coil of the receiving or intermediate circuit. Loosely coupled with I the coil of one of the parallel branches is an oscillation circuit which is tuned to the incoming Wave. Now,if the proportions of-the coils and the degree of the coupling are so chosen that with opened or disconnected'resonance circuit the potentials induced in the receiving circuit are compensated mutually, the tuned or resonance circuit which is tuned to the incoming wave and is coupled with one of the parallel branches, causes the symmetry of the circuit arrangement for this incoming wave to cease, that is to say, on account of reaction the apparent resistances (impedances) of the two parallel branches are subject to marked variation, and the energy is transferred to the receiving circuit. However, for waves differing in length from the receiving frequency, for instance, for the localtransmitter 1n duplex arrangements, the reaction of the loosely Y J coupled resonance CllCllliklS negligible so that anearly perfect compensation of these potentials in the receivingcircuit is attained.

For further explanation of the invention,

reference is made to Fig. 1. The. receiving aerial A contains the two parallel connected COll branches L and L which are brought to cuit tuned to the incoming wave E. In the case of radio frequency intelligence transmission along lines, the differential transformer consisting of the three coils L L ,"and L is I inserted in the coupling lead to which the receiver circuit, or the receiver and transmitter circuits in case of duplex operation, are united. An arrangement of this kind is illustrated in Fig. 2. The additional tuning means there shown serve for the purpose of making the circuit two-wave in nature so that the same is tuned both to the transmission as well as the incoming Wave. As can be read ily seen, the sending oscillations are precluded from the receiving circuit by an arrangement as there illustrated. The circuit arrangements here suggested are further. of advantage in order to preclude aperiodic disturbances of the kind caused by atmospheric dis charges from the receiving system.

I claim:

1. A receiving arrangement adapted for interference elimination comprising an an-v tenna circuit, two coupling means energized thereby, a receiver, means. to couple said receiver to each of said two coupling means in opposition, and means affecting one of said coupling means to make it a rejector circuit for a desired frequency.

2. in combination, an-antenna circuit in-, cluding two branches inparallel, a receiver, means to couple said receiver to the antenna circuit, said means being coupled to both of parallel branches'in opposition, and a resonant circuit coupled to one j of said branches.

In combination, an antenna circuit including two branches in parallel, a receiver, means to couple said receiver to the antenna circuit, said means being coupled to both of said parallel branches in opposition, and

eluding two branches in a resonant circuit tuned to the frequency of a desired Wave coupled to one of said parallel branches. 7 V

4. In combination,

parallel, a receiver, means to supply energy circuit to said receiver, said means being coupled to both of saidbranches in oppo sition, branches :1 injector-circuit.

5. In combination, an antenna circuit including parallel branches, means to tune said antenna circuit simultaneously to two frequenoies, a" transmitter tuned to one of said trequencles coupled to said antenna circuit,

a: receiver tuned to the other frequency,

an antenna circuit infrom said antenna I and means to make one of said" means to supply energy from said antenna circuit to said receiver coupled to both of the parallel branches in opposition, and means to make one of the parallel branchesa recomprising tWo parallel connected coils connectcd thereto anda third coil, receiving means connected to said last named coil and acted upon by both of said two parallel con nected coils andtan oscillation circuit in loose coupled relationship with onlyone of said first two mentioned coils.

WALTER WURS'r. 

